This invention relates generally to gas turbine engines, and more specifically to heat shields used with gas turbine engine combustors.
A gas turbine engine typically includes a core engine having a serial flow arrangement, a high pressure compressor which compresses airflow entering the engine, and a combustor which burns a mixture of fuel and air. The combustor consists of a dome assembly at a forward end of the combustor, and liners, which contain the hot products of combustion and direct them toward the turbine. The fuel injector is aligned with holes in the combustor dome that are specifically designed to mix incoming fuel with air at a proper ratio for burning. Since the products of combustion may exceed the thermal capabilities of any metal parts, the products of combustion are prevented from directly contacting structural metal parts. To facilitate insulating structural components from the products of combustion, at least some known combustor dome assemblies include a structural dome plate that provides support to the liners, and a heat shield that insulates the structural elements from the hot products of combustion.
Cooling air is supplied to surfaces of structural elements that are exposed to the higher temperature combustion gases. More specifically, in at least some known combustor dome assemblies, the dome plate includes impingement cooled heat shields which are cooled as cooling air is accelerated through small holes in the dome to impinge on a forward surface of the heat shield. After impinging on the heat shield forward surface, the cooling air enters the combustor around the edges of the heat shields. However, cooling air is needed in many parts of the engine, and in at least some known advanced high pressure ratio engines, the need for cooling air may begin to exceed supply. As a result, continued exposure to high temperatures by an aft surface of the heat shields may decrease the useful life of combustor assemblies that include domes.
In one aspect of the present invention, a combustor for a gas turbine including a dome assembly that facilitates extending a useful life of the combustor in a cost-effective and reliable manner is facilitated. The dome assembly includes a dome plate and a heat shield coupled to the dome plate. The dome plate includes an impingement baffle and an opening extending therethrough for receiving a fuel injector. The impingement baffle also includes a plurality of cooling openings that extend therethrough and are in flow communication with the heat shield.
In another aspect, a combustor for a gas turbine engine is provided that includes a dome assembly including a dome plate and a heat shield coupled to said dome plate. The dome plate includes an impingement baffle and a fuel injector opening that extends therethrough. The impingement baffle is configured to direct air for impingement cooling and film cooling of said heat shield.
In a further aspect of the invention, a method for supplying airflow to a gas turbine engine combustor through a dome assembly is provided. The dome assembly includes a dome plate and a heat shield. The dome plate includes an impingement baffle, and the heat shield is coupled to the dome plate. The method includes the steps of directing compressed airflow to the impingement baffle, and redirecting airflow towards the heat shield with the impingement baffle for impingement cooling and film cooling of the heat shield.